1. Field of the Invention
The present invention relates to a simulated wood tone member which is used in, for example, steering systems for vehicles or boats, housing, and the like, and to a method of manufacturing the simulated wood tone member.
2. Description of the Related Art
Urethane steering wheels having a simulated wood tone member have been conventionally used in steering systems for vehicles, boats and the like.
This urethane steering wheel is formed by molding by injecting a urethane based composition into a mold in which a wood grain pattern is formed by etching, and then curing the injected urethane based composition. In this way, as illustrated in FIG. 6, recesses 52 of uniform depths are formed in the surface of a urethane steering wheel 50. By filling a wood filler 54, which has good concealability, into the recesses 52, edge grain vein-like portions appear, and the wood grain pattern decorates the surface of the urethane steering wheel 50. Further, the wood filler 54 contains 30% toner, and the toner contains 5% black pigment.
However, because the recesses are formed to the same depth, gradation (shading) of the wood grain pattern cannot be exhibited, such that it is difficult to obtain a beautiful wood appearance with attractive wood grains.
A first aspect of the present invention is a simulated wood tone member comprising: (a) a urethane-based base member having a surface with recesses formed to different depths and forming a pattern; and (b) a wood filler disposed in the recesses, the wood filler being substantially transparent and comprising at least one coloring agent.
In accordance with this structure, recesses are formed to different depths in the surface of the urethane based base member. Therefore, gradation of the pattern can be expressed. By filling-in in the recesses a wood filler which is transparent and which contains a coloring agent, the shading can be made to vary in accordance with the depths of the recesses. For example, if the pattern is a wood grain pattern, a wood grain pattern with an attractive wood appearance can be expressed.
In the first aspect of the present invention, it is preferable for the angle portions of the recesses and for the corner portions of the bottom portions of the recesses to be formed at right angles.
In accordance with this structure, because the angle portions of the recesses and the corner portions of the bottom portions of the recesses are formed at right angles, the wood filler can be reliably filled into the recesses, and the pattern can be expressed reliably.
Further, in the first aspect of the present invention, it is preferable that the transparency of the wood filler is of an extent that light can reach the bottom portions of the recesses.
In accordance with this structure, the wood filler is transparent to the extent that light can reach the bottom portions of the recesses. Thus, the shading of the pattern, which corresponds to the depths of the recesses, can be clearly formed.
A second aspect of the present invention is a method of manufacturing a simulated wood tone member, comprising the steps of: (a) etching a mold in a plurality of stages to thereby form a wood pattern due to corrosive differences; (b) forming an in-mold coating layer at an inner side of the mold; (c) injecting a urethane-based composition into the mold; (d) removing a urethane mold from the mold, formed by the urethane-based composition hardening, the urethane mold having wood grain portions; (e) filling the wood grain portions with a wood filler that is substantially transparent and comprises at least one coloring agent; and (f) forming a substantially clear color layer on the urethane mold.
A third aspect of the present invention is a method of manufacturing a simulated wood tone member comprising the steps of: (a) forming inner surface recesses of various depths in a mold by applying masking to a predetermined position of the mold, etching the mold, and etching at least one more time, with the position of the masking changed; (b) injecting a urethane-based composition into the mold; and (c) removing from the mold a urethane mold formed by the urethane-based composition hardening.
In the simulated wood tone member formed by the steps of the second and third aspects of the present invention, the recesses are formed to different depths. Therefore, gradation can be imparted to the wood grain pattern formed on the surface of the simulated wood tone member. By filling-in in the grains the wood filler which is transparent and contains a coloring agent, variations in the wood grain colors can be realized. As a result, a wood grain pattern having an attractive wood look can be expressed.